1. Field of the Invention
The present invention relates to an electromagnetic actuator and in particular to an electromagnetic actuator having an elongated stator for production of high pull in forces.
2. Description of the Prior Art
It is commonly known to use a current introduced into a coil of wire to produce an electromagnetic force which is localized with the addition of an iron core or stator which is used to attract a hinged magnetically active armature in some fashion to provide motion. Traditionally, the coil is cylindrical in shape and fitted over one leg of the stator. For many applications, this particular configuration has proved to be satisfactory. However, it would be desirable to utilize a different coil and stator shape for the actuator to provide an increase in draw-in force at the moveable armature for performing a variety of tasks. In the prior art, a relay is formed with an armature and a magnetic assembly where the armature is connected to one or more electrical contacts which require a relatively low force to make and to break a connection. However, for use in other applications other than cylindrical relays, much higher force levels and/or increased travel is required to perform the necessary motion.
The electromagnetic actuator described in U.S. Pat. No. 4,099,151, the disclosure of which is hereby expressly incorporated by reference, discloses a stationary stator structure and a moveable armature structure where the armature is drawn toward the stator using a single coil of electrical wire wrapped around one side of the stator. The coil is formed in a cylindrical shape with an armature hinge point on a support structure. In a similar manner, U.S. Pat. No. 4,447,794 discloses a stator construction where an armature is hinged to be rotated on a second leg of a stator of an electromagnetic actuator where a coil is wound around a first leg with the first leg and second leg being joined to form one electromagnetic conductive path. U.S. Pat. No. 4,447,794 is hereby expressly incorporated by reference. These particular coil and stator constructions do not lend themselves to certain applications where high force and long travel are required of the actuator.